In a technical field related to such antenna, as is generally known, various types of antennas are mounted to a vehicle. For example, a GPS (Global Positioning System) antenna, an ETC (Electronic Toll Collection System) antenna, a VICS (Vehicle Information and Communication System) antenna, a telephone antenna and the like are mounted to the vehicle.
Specifically, the GPS (Global Positioning System) employs a satellite positioning system by use of a satellite. The GPS receives electric waves such as GPS signals from four satellites out of twenty-four earth-orbiting satellites. By measuring a positional relation and a time error between a movable body on the earth and the satellite, on the basis of a principle of a triangular surveying, the GPS computes a position and an altitude of the movable body on a map or the like with high accuracy.
The GPS is used for a car navigation system or the like for detecting a position of a running vehicle, and such system has been widely used. A car navigation device with the car navigation system includes a GPS antenna, a processing device, a displaying device and the like. Specifically, the GPS antenna receives the GPS signal from the satellite, the processing device detects a current position of the running vehicle by processing the received GPS signal, and the display device displays the detected current position of the running vehicle on a map or the like.
The ETC (Electronic Toll Collection) is a system, which was developed for easing traffic jams at tollgates, at which a passenger pays a toll for a toll road. Specifically, the ETC is a system by which the toll is automatically paid by the passenger at the tollgate by means of a wireless communication system. More specifically, the vehicle equipped with a communicating device having an ETC antenna establishes two-way communication with an antenna provided at the tollgate in order to receive information from the vehicle, and the toll fee can be paid automatically at the tollgate without requiring the vehicle to stop.
A known compound antenna apparatus equipped with the GPS antenna, the VICS antenna and the ETC antenna is disclosed in JP2004-56773A. According to the know compound antenna apparatus, because directional characteristics of the ETC antenna differs from that of the GPS antenna and the VICS antenna, the GPS antenna and the VICS antenna are mounted to a circuit board, and the ETC antenna is independently mounted to the vehicle as a sub assembly. In this structure, when those antennas are mounted to the vehicle, a direction of the ETC antenna can be controlled separately from that of the GPS antenna and the VICS antenna.
Further, a telephone antenna in which inverted L element, serving as a feed element, is positioned so as to be close to parasitic element, serving as a passive element, is also generally known as a wide band antenna having a wide frequency range such as a cellular antenna for a vehicle.
According to the known compound antenna apparatus disclosed in JP2004-56773A in which the telephone antenna in which inverted L element, serving as the feed element, is positioned so as to be close to parasitic element, serving as the passive element, it is preferable that inverted L element and parasitic element are easily mounted without having variations on a geometrical tolerance and a dimensional tolerance thereof.
A need thus exists to provide an antenna apparatus at which a feed element and a passive element can easily be mounted without having variations of a geometrical tolerance and a dimensional tolerance as possible so that the antenna apparatus is not adversely affected by such variations.